Code review comment for lp:~jonathan-stoppani/txamqp/catch-closed-queues

Sorry for the delay, thanks Jonathan for your patch. It looks great, I just made some small modifications (lp:~esteve/txamqp/catch-closed-queues) to it:

- separated handling of client's and server's errbacks
- added two empty functions (handleClientQueueError and handleClosedServerQueue), which can be overridden by subclasses to provide more fine-grained error handling

Let me know what you think of them. Thanks!